remove tab in docker files and remove libebook
ensure that all docker files have no tabs in the list of software to install:
Saw in Dockerfile_debian_10_arm64 that is a copy of the copy ... of debian Dockerfiles:
libcanberra-gtk3-dev \
Reference: https://review.jami.net/c/ring-project/+/13280/12/docker/Dockerfile_debian_10_arm64#23